Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice newton's colour disc light and the formation of shadows physics

When a drop of water is introduced between the glass plate and plano-convex lens in Newton's rings system, the ring system

  1. Contracts

  2. Expands

  3. Remains same

  4. First expands then contracts
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The diameter of Newton's rings is inversely proportional to refractive index. Therefore when a drop of water is introduced between the glass plate and plano-convex lens in Newton's rings, the ring system contacts. 

Multiple choice newton's colour disc light and the formation of shadows physics

Rainbow is observed when the Sun is 

  1. In front of the observer

  2. Behind the observer

  3. Vertically above the observer

  4. In any of these position
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sun is always behind the observer. This is because the rainbow is actually just sunlight which has been refracted and reflected.

Multiple choice newton's colour disc light and the formation of shadows physics

In the Newton's rings set up, when a drop of water is introduced between the glass plate and planoconvex lens the observed ring system

  1. Contracts

  2. Expands

  3. Remains the same

  4. Expands and then contracts
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Since diameter of the ring is inversely proportional to the square root of refractive index of the medium between the planoconvex lens and plane glass plate, therefore as refractive index increases, diameter of the rings decrease, that is the rings contract. 

Multiple choice newton's colour disc light and the formation of shadows physics

In Newton's experiment the radii of the $m^{th}$ and $(m+4)^{th}$ dark rings are respectively $\sqrt{5}$mm and $\sqrt{7}$mm. What is the value of m?

  1. $2$

  2. $4$

  3. $8$

  4. $10$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Radius of mth dark fringe   $r _m = \sqrt{mR\lambda}$
Thus we get  $r _{m+4} = \sqrt{7} = \sqrt{(m+4)R\lambda}$     ......(1)
Also,  $r _m = \sqrt{5} = \sqrt{mR\lambda}$      .......(2)
Dividing equation (1) with equation (2),  
$ \sqrt{\dfrac {m+4}{m} }= \sqrt{\dfrac{7}{5}}$
$\dfrac{m+4}{m} = \dfrac{7}{5}$
$5(m+4)= 7m$
$5m+20= 7m$
$2m=20$
$\implies   \ m=10$

Multiple choice physics the universe types of galaxies galaxies constellations
Fill in the blank:
A vast collection of billions of stars is called a _______.

  1. universe

  2. galaxy

  3. constellation

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Galaxy is a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
Earth is is Milky way galaxy.
Multiple choice physics the universe types of galaxies galaxies constellations

According to best estimates today, how old is the universe ?

  1. between ten and twenty thousand years.

  2. between ten and twenty million years.

  3. between ten and twenty billion years.

  4. between ten and twenty trillion years.

  5. between ten and twenty quadrillion years.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The age of universe is approximately 13.82 billion years. It is the time that has passes since the Big Bang that started the building of matter, time and space itself. Time had no existence before the Big Bang.
Hence correct answer is option C.

Multiple choice physics the universe types of galaxies galaxies constellations

Which of the following provides clear evidence that the universe is expanding ?

  1. the Oort cloud

  2. the Kuiper belt

  3. Saturn's ring

  4. Halley's comet

  5. the red shift of distant galaxies
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The spectrum of light coming from galaxies have spectral lines of hydrogen ,sodium etc. We compare the spectral lines obtained from galaxy to the spectral lines obtained in laboratory of the same element .If the spectral lines of galaxy are shifted towards the red end of the spectrum (red shift) it means the galaxy is going away from earth . This implies that universe is expanding .This is one of the applications of Doppler's effect .

Multiple choice physics the universe types of galaxies galaxies constellations

Community or collection of stars is called:

  1. solar system

  2. galaxy

  3. planet

  4. milky way
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The solar system is the planetary system, where we live. It consists of the Sun and its planets, including the Earth.

A galaxy is a collection of millions of stars which are bound together to form a specific shape.
Planet is a body which revolves around a star. For eg:- The earth is a planet of the Sun which is a star.
Milky Way is the name of our galaxy. The sun and the earth are in the Milky Way.